Flight profile · Delta Air Lines
DL473
Seattle (SEA) to Boston (BOS) · scheduled 10:05 PM – 7:55 AM
How DL473 performs
782 operations, June 2024 – July 2026.
DL473 arrived on time 84.0% of the time, against 75.2% for all SEA → BOS flights, so this departure is 8.8 percentage points better than the route as a whole.
Source: US DOT Bureau of Transportation Statistics · 782 operations, June 2024 – July 2026 · If DL473 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where DL473 is right now
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Against the rest of the route
| Flight or route | On time | Cancelled | Median delay | Severe | Flights |
|---|---|---|---|---|---|
| DL473 | 84.0% | 1.41% | -8 min | 2.5% | 782 |
| Delta Air Lines on SEA → BOS | 83.9% | 1.07% | -9 min | 4.5% | 2,980 |
| All SEA → BOS flights | 75.2% | 0.94% | -4 min | 7.6% | 7,902 |
Source: FlyerIntel analysis of US DOT BTS data · June 2024 – July 2026
Why DL473 runs late
Where US DOT attributed the delay minutes on this flight.
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for DL473 on SEA → BOS. Only delays of 15 minutes or more are attributed.
Source: US DOT Bureau of Transportation Statistics · Data covering June 2024 – July 2026
Does a late aircraft delay this flight?
How often the plane that flies DL473 comes in late, and what that does to the departure.
When the aircraft came in 15 or more minutes late, DL473 pushed back an average of 22 minutes late; when it came in on time or early, an average of 2 minutes late.
Each departure is matched to the flight the same aircraft flew into SEA just before it, using the tail number in the DOT file, 577 of 774 departures in all. A departure is left out when that flight is unknown, was cancelled or diverted, or the aircraft had sat for more than 12 hours. A flight the airline cancelled never left and is not in the count, and one flown by a substitute aircraft is matched to the aircraft that flew it, not to the one first planned.
Against the network at the same turn length
| Share of departures | Inbound landed 15+ late | Left 15+ late after a late inbound | Left 15+ late after an on-time inbound |
|---|---|---|---|
| DL473 | 22% | 50% | 9% |
| Network, same turn | 17% | 68% | 9% |
The schedule leaves a normal turn: enough time to clean and board if the aircraft is on time, little to spare if it is not.
The network row is every flight with a scheduled turn of 60 to 89 minutes. How often DL473’s aircraft landed 15 or more minutes late is higher than the network’s and, once the aircraft was late, how often DL473 left 15 or more minutes late is lower than the network’s.
More: Which Flight Numbers Pay for a Late Aircraft lists the flight numbers that pass a late aircraft on.
Source: US DOT Bureau of Transportation Statistics · Data covering June 2024 – July 2026
From pushback to gate
When it leaves SEA late, does that still matter by the time it reaches BOS?
DL473 pushes back an average of 7.9 minutes late and reaches the gate at BOS an average of 3.9 minutes early. The 11.8 minutes between those two figures are slack the published schedule already carries, which is why a late pushback on this flight does not reliably become a late arrival. Its 19.9 minutes on the taxiways at SEA is about what any departure from the airport in that hour spends.
On arrival at BOS, DL473 spends 14.3 min taxiing from touchdown to the gate — ground time a connecting passenger sits through before they can even leave the aircraft, on top of however late the flight itself ran. That is 5.3 minutes longer than a typical BOS arrival (9.0 min).
Departure delay is averaged over every pushback and arrival delay over every completed arrival, so the two counts differ by the flights that never reached BOS. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 17,895 departures from SEA scheduled in the clock hour DL473 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at BOS (440,886 flights), not just DL473’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · June 2024 – July 2026
The hour it leaves SEA
Part of any flight’s record belongs to the clock rather than to the flight. DL473 has one departure time, so this is what that time is worth.
On-time arrival rate. 17,895 departures from SEA are scheduled in the 10 PM–11 PM hour over the period, against 510,205 across the whole day.
DL473 is scheduled out of SEA at 10:05 PM, in the 10 PM–11 PM bank. Departures from SEA in that hour arrive on time 74.1% of the time against 79.1% across the airport’s whole day — the slot alone is worth 5.0 points worse before anything about this particular flight is considered.
The two airport figures cover every departure from SEA to every destination, so they describe the slot rather than this journey — the like-for-like comparison against the route is above. Hours are scheduled local, and a number whose schedule moved between banks inside the period has no single hour and is not described here at all. Why the hour matters.
Source: FlyerIntel analysis of US DOT BTS data · June 2024 – July 2026 · Hours below 120 departures are not scored.
Other routes DL473 has flown
A flight number is a slot in a schedule, and carriers reassign it. These are the other city pairs this number served in the analysis period.
| Route | Operated | Flights | On time |
|---|---|---|---|
| LAX→BNA Los Angeles to Nashville | July 2, 2023 – June 6, 2024 | 95 | 92.6% |
| SAN→ATL San Diego to Atlanta | April 9, 2024 – May 6, 2024 | 28 | — |
| STL→SLC St. Louis to Salt Lake City | March 10, 2024 – April 8, 2024 | 30 | — |
| LAX→ATL Los Angeles to Atlanta | January 8, 2024 – March 9, 2024 | 62 | — |
| MIA→LGA Miami to New York | July 1, 2023 – December 30, 2023 | 14 | — |
| LGA→MIA New York to Miami | December 17–30, 2023 | 12 | — |
| FCA→MSP Kalispell to Minneapolis | December 16, 2023 | 1 | — |
| BOS→LAX Boston to Los Angeles | September 5, 2023 – December 15, 2023 | 100 | 89.9% |
| IAD→ATL Washington to Atlanta | November 23–24, 2023 | 2 | — |
| BNA→LAX Nashville to Los Angeles | July 2–9, 2023 | 7 | — |
Because the same number has served different journeys, the statistics above describe only the route DL473 currently operates. Blending them would produce an average of two different flights.
When it goes wrong
The average describes a usual day. This is the day that ruins a connection.
24 min late
against a median of 8 min early
Percentiles over 782 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering June 2024 – July 2026
Other flights on this route
Same airports, same journey, different odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| DL459 | Delta Air Lines | 89.4% | 14 min early | 785 |
| DL473 this flight | Delta Air Lines | 84.0% | 8 min early | 782 |
| AS306 | Alaska Airlines | 77.6% | 4 min early | 1,114 |
| AS460 | Alaska Airlines | 75.0% | 3 min early | 1,065 |
| AS536 | Alaska Airlines | 72.7% | 1 min early | 811 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. DL473 is placed in the same ordering rather than left out of it; the rows around it are the most punctual departures on the route, not all of them, so this is a comparison and not a rank. Schedules change; confirm the departure still operates before booking around this.
Data and methodology
Calculated by FlyerIntel from 782 records of DL473 operating SEA → BOS, published by the US DOT Bureau of Transportation Statistics. A flight counts as delayed when it arrives 15 or more minutes after schedule. Cancelled and diverted flights are excluded from the on-time rate and reported separately. Flight numbers are resolved as carrier plus number plus route, because the same number serves different routes over time.
Full methodology · Data sources · Report a problem
Related research: Most and Least Reliable Flight Numbers · The Delay You Inherit · Making Up Time in the Air
Analysis last recomputed